1. Field of the Invention
The present invention relates to a headrest provided at an upper portion of a backrest of a seat mounted on a vehicle, and more particularly to a device for moving up and down and tilting the headrest relative to the backrest.
2. Description of the Related Art
When a backrest of a front seat of a vehicle is tilted backward to form, together with a rear seat cushion, a flat, fully reclined support for the seat occupant, a headrest provided on the front seat backrest must be moved to a position at which it will not collide with the rear seat cushion when the backrest of the front seat is thus tilted backward. Also, when the vehicle is driven in reverse, for example, the headrest of the front seat backrest may intrude into the field of vision of the driver, and therefore, in this case, the headrest should be moved out of the way to a position below the upper portion of the seat backrest.
In consideration of the above points, Japanese Unexamined Patent Publication No. 60-244632 disclosed a vehicle seat having a headrest which can be tilted to a position adjacent to a back face of a front seat backrest. However, this headrest of the vehicle seat cannot be moved to such a position on the seat backrest until the headrest is first lifted to an upper limit position at which the leg members of the headrest are released from a stopper in the seat backrest, and such a movement is time-consuming and cumbersome, particularly when the headrest has been set at a low position relative to the top of the seat backrest.
Japanese Unexamined Patent Publication No. 61-249411 discloses a construction in which a headrest of a front seat backrest is tilted by a mechanism which also moves the headrest up and down. However, in this construction, the leg members of the headrest interfere with an inner surface of the backrest if the headrest is not lifted to a certain extent, and therefore, the time needed to move the headrest to a predetermined position is relatively long. Conversely, if the headrest is constructed so that it can be tilted without first lifting, a larger space in the front seat backrest must be allowed to accommodate the necessary mechanism.